A federal judge prevented a West Virginia public school from proceeding with its single-sex classes, saying parents didn't get a fair chance to withdraw their kids. But the question of whether single-sex classes work or are built on unhelpful gender stereotypes gathers pace.

Dillon Elledge, 8, (r.) and Brody Kemble, 7, work with flash cards in their all-boys classroom at Middleton Heights Elementary in Middleton, Idaho, in May. Middleton is believed to be the only public school in Idaho offering all-boy and all-girl classrooms, though the movement is widespread in other states and is now being targeted by the American Civil Liberties Union.

Separate classes for girls and boys at Van Devender Middle School in Parkersburg, W. Va., have to be reorganized into coed classes by Monday, a federal judge ruled this week.

The injunction comes after a mother and her daughters, represented by the American Civil Liberties Union, alleged that the school was using pseudoscience and gender stereotypes to teach boys and girls, and that the different methods harmed them academically and violated their civil rights.

One of the girls, diagnosed with attention-deficit disorder, alleges she was frequently reprimanded for not sitting still, while boys were encouraged to move about their classroom. Another, legally blind, alleges the lights were not bright enough in her classroom because the teachers have been told that girls respond better to a different kind of light.

Wood County district officials deny the allegations, and one single-sex education expert who testified on behalf of the school agrees, saying she thought the approaches in the classroom were thoughtful, rather than based on stereotypes.

But as a tiny but growing number of public schools – about 1,000 by one estimate – offer full programs or individual classes for boys and girls in separate settings, the Van Devender case highlights the debate about whether such programs are important experiments in closing achievement gaps or a reinforcement of troubling gender stereotypes.

Under Title IX, a federal law prohibiting sex discrimination in education, public schools can offer single-sex classes if they meet criteria outlined in 2006 regulations from the US Department of Education. The classes have to be “substantially related” to achieving specific educational objectives. They also have to be voluntary, and students must be offered an equivalent coed alternative.

Parents had been given notice that students could opt out, but too close to the start of the school year. Judge Goodwin ruled that in order for the classes to comply with Title IX, parents would have to give their “affirmative assent,” preferably in a written document opting into the program.

Although the ruling is not binding in other parts of the country, it could prompt many school districts nationwide to adopt an opt-in policy for single-sex classes.

Both opponents and proponents of single-sex classes in public schools, however, found something to cheer in the opinion, which did not rule out the possibility of single-sex classes at the school in the future.

“The most important thing is our clients are going to coed classes next week,” says Amy Katz, cooperating attorney with the ACLU Women’s Rights Project in New York. If there is a future program in the district, she says, “it can’t be mandatory, and we don’t think most people would even elect to put their kids into single-sex classes.”

But Goodwin put a damper on some of the broader arguments the ACLU has offered in opposing single-sex classes in public schools: “The plaintiffs, in essence, take the position that no single-sex classes would ever withstand scrutiny under the Constitution or Title IX. The court finds this argument unpersuasive.”

District officials were disappointed to have to temporarily halt the program but see the opinion as largely in their favor. At this point, the program “could resume this next school year” after some changes, says director of secondary education Mike Winland. “We feel strongly that this program was working.”

Van Devender started its single-sex classes in reading, math, social studies, and science for sixth-graders in 2010. The single-sex approach expanded to seventh-grade last year and eighth-grade this year.

By the end of seventh-grade, students who were in single-classes for two years made larger gains on state tests than peers at coed middle schools, Mr. Winland says. Teachers and students both noticed more focus in the classroom, because there was less posturing to impress the opposite sex.

Such outcomes are often touted by Leonard Sax, a speaker and consultant who trains teachers based in part on the idea that brain-science suggests there are physiological differences between boys and girls.

Mr. Sax visited a school in Dallas recently, for example, where low-income minority boys working in competitive teams were so motivated that they demanded more books so they could earn extra credit. An equivalent school for girls is also doing well, says Sax, founder and executive director of the National Association for Single Sex Public Education.

Why shut down a school like that, he wonders, when educators are desperately trying to close achievement gaps?

The judge noted in Wednesday's opinion that some of Sax’s strategies seem to be based on pseudoscience and stereotypes. Winland says that contrary to the ACLU’s accusations, the Van Devender program does not rely much on his research.

Rosemary Salomone, author of "Same, Different, Equal: Rethinking Single-Sex Schooling" and an expert witness for the school, tells the Monitor that “my position is nuanced.”

“I oppose the brain-science research of Leonard Sax," says Professor Salomone, who is a law professor at St. John's University in New York and helped write the revised regulations to Title IX in 2006. "On the other hand, I do believe these [single-sex] programs can be implemented with Title IX compliance.”

The ACLU and other groups such as the Feminist Majority have called on the Department of Education to rescind the 2006 regulations.

Hypothetically there are some good single-sex programs, says Ms. Katz, but “there are so few of them that we’d be better returning to the old regulations because the bright line standard was much better.”

“We are considering whether further guidance on this topic may be appropriate," writes Daren Briscoe, a spokesman for the Department of Education, in an e-mail. In addition, the department is now tracking the number of single-sex classes in public schools in the Civil Rights Data Collection, he notes.

The ACLU has prompted a number of schools to stop single-sex programs after pointing out ways in which they appeared to violate the law. In the Van Devender case, it must now decide whether to pursue the case in hopes of a permanent ruling.